Which of the following has highest boilling point ?

Options

A. 1-chloropentane
B. 2-chloropentane
C. 3-chloropentane
D. All have equal boilling point

Answer

To determine which compound has the highest boiling point among the given options, we can follow these steps:

### Step 1: Understand the Factors Affecting Boiling Point
The boiling point of a compound is influenced by:
- **Molecular Weight**: Higher molecular weight generally leads to higher boiling points.
- **Branching**: More branching in the molecular structure leads to a decrease in boiling point due to a reduction in surface area, which decreases the intermolecular forces of attraction.

### Step 2: Analyze the Given Compounds
Assuming we have three haloalkanes where the only difference is the position of the chlorine atom, we can denote them as:
1. Compound A: CH3-CH2-CH2-CH2Cl (Chlorine at the end)
2. Compound B: CH3-CH(Cl)-CH2-CH3 (Chlorine in the middle)
3. Compound C: CH3-CH2-CH(Cl)-CH3 (Chlorine in the middle but with different branching)

### Step 3: Compare the Structures
- **Compound A** has a straight-chain structure with no branching.
- **Compound B** and **Compound C** have branching due to the position of the chlorine atom.

### Step 4: Determine the Effect of Branching
Since Compound A has no branching, it will have a larger surface area compared to Compounds B and C. The presence of branching in Compounds B and C will lead to weaker intermolecular forces due to the reduced surface area.

### Step 5: Conclude the Boiling Point Comparison
Given that:
- Compound A has the highest molecular weight and no branching,
- Compounds B and C have branching which decreases their boiling points,

We conclude that **Compound A** has the highest boiling point among the three.

### Final Answer
The compound with the highest boiling point is **Compound A**.

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